Fluazinam and its mixtures induce diversified changes of crucial biochemical and antioxidant profile in leafy vegetable

Fungicides applied singly are frequently used to ensure disease control in the cultivation of leafy vegetables. The behavior of fungicide mixtures and their impact on plant biochemical and antioxidant status was poorly investigated. The main goal of this study was to compare the impact of fluazinam, a separately applied fungicide, and its mixtures (dithianon+fluazinam, dodine+fluazinam) during dissipation on biochemical compounds and the antioxidant profile in lettuce. Additionally, the behavior of dithianon and dodine applied singly was examined. We noted a longer dissipation time of fluazinam in mixtures (DT50= 6.31 and DT50=4.80) compared to separate application (DT50= 3.36) as well as a shortened dithianon and dodine degradation in mixtures. Moreover, dithianon, dodine and fluazinam applied separately affected the reduction of chlorophylls (43%) and carbohydrates (56%) as well as the induction of carotenoids (37%), protein (40%) and phenolic compounds (50%) in a different dissipation time. Furthermore, fluazinam mixtures intensified accumulation of carotenoids (up to 106.1 mu g g(-1)), protein (21.9 mg g(-1)) and phenolic compounds (1410 mu g g(-1)), while reduction of carbohydrates (3.4 mu g g(-1)), compared to separate application. For the first time, we revealed that non-enzymatic antioxidants are the first line of defense in ROS scavenging caused by fungicides (up to the 12th h), while antioxidant enzymes (CAT, POD, SOD) play a secondary role in supporting stress mitigation. Results of the study can be applied to the horticultural practice in lettuce cultivation and shed a new light on plant biochemistry under fungicide stress conditions.

Automated summary

This study compared the impact of separately applied fungicides and mixtures on the biochemical compounds and antioxidant profile in lettuce. It found that mixtures of fungicides had a longer dissipation time and intensified the accumulation of certain beneficial compounds, but reduced carbohydrate levels. Additionally, non-enzymatic antioxidants played a critical role in scavenging reactive oxygen species caused by fungicides.